1. Field of the Invention
The present invention pertains to a security technology used when e-mail is transmitted, and more particularly, to a technology that discovers ‘impersonation’ when e-mail is transmitted.
2. Description of the Related Art
In the conventional art, various technologies have been proposed to confirm the identity of other party when data is transmitted or received over a network. For example, in Japanese Laid-Open Patent Application H11-27489, a technology is disclosed in which, during facsimile transmission, the receiving facsimile mail apparatus reads an e-mail address included in the received facsimile mail message and identifies the sending facsimile apparatus, and returns a notification of receipt. With such an apparatus, by receiving the notification of receipt, the sending facsimile apparatus can confirm the identity of the facsimile mail apparatus to which the message was sent, and at the same time, where a false e-mail address is sent, because the notification of receipt is returned to the person whose address was used without authorization (hereinafter referred to as the ‘proper account holder’), so-called ‘impersonation’ in which an e-mail is sent via the address of another through deceit, can be discovered.
Furthermore, a technology known as ‘POP Before SMTP’, in which one's own password-protected account is accessed and a message can be sent only after it is confirmed that one is the actual user of that account, is also known. With this technology, even for communications using SMTP and the like, which lack a function to validate the sender's identity, ‘impersonation’ can be prevented because data cannot be sent via the address of another.
However, from the standpoint of preventing or discovering ‘impersonation’, the technology used in the facsimile apparatuses described in the above laid-open patent application entails the problem that it requires the receiving facsimile to be equipped with a function corresponding to the technology used. Moreover, because a notification of receipt is returned at all times when a facsimile mail message is sent, the problem of increased network load arises. In addition, the problem exists that the desire to check the contents of the sent email message that was falsely identified through ‘impersonation’ cannot be accommodated.
Furthermore, the ‘POP Before SMTP’ technology described above entails the problem that one's own account must be accessed when sending is performed, requiring operations such as password input to be performed.